Android 12 officially released about a week ago. If you want to use it but you do not have it in the settings, simply download it from the Zenfone8 support page and drag the zip on the phone storage with a computer. When its done transfering, you can unplug the phone, reboot the phone and wait a bit (a minute or so). The phone will ask you to install an update just click yes it will start the update process.